Helicopters: How They Work
The V-22 Tiltrotor

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No matter what is currently going on in aviation, everyone always asks, "What is next"? As you probably have learned from this site, or others like it, helicopters have a very limiting factor common to all of them; Airspeed. The question for many has always been how to get around this limitation. How do we make a helicopter that will take off vertically and go faster than conventional helicopters, then land again vertically as it took off?

One answer to this question has been the very successful AV-8 series of airplanes known as the Harrier . While the AV-8 Harrier has been a success for military operations, it is impractical for civil use due to the large quantities of fuel required to maintain a hover and the amazing amount of noise produced by the engine to maintain vertical flight.

Other projects have been undertaken such as the Advancing Blade Concept (ABC), The Cheyenne Project and numerous Tilt-wing aircraft. None of these concepts were pursued to completion for one reason or another. Another project that was attempted was the Fairey Rotodyne (Gyroplane concept) project which was successfully flown, but had many noise problems as well and was never really accepted for civilian use.

This is the Advancing Blade Concept aircraft. Notice that it looks a lot like both an airplane and a helicopter. The side mounted jets were to push the aircraft along using jet thrust as the primary means of propulsion. It has contra-rotating (Contra...not counter) rotors mounted co-axially (One on top of the other)to eliminate retreating blade stall characteristics.

This "Tilt-wing" design is unlike the "Tilt-Rotor" in that the whole wing tilts and not just the engine nacelles. A design like this loses the lift generated by the wing at lower speed and is less versatile than a pure "Tilt-Rotor" design. The engines could only lift it straight up and it had no form of helicopter controls.

The Rotodyne used jet thrust at the rotor blade tips to propel the rotor to a high speed for takeoff and landing. The rotor would be unloaded in flight and the aircraft would fly like an airplane at cruise speeds. The major problem with this was the noise created by the jet powered rotor system.

The V-22

Enter the V-22, one of the most controversial aircraft to ever be built and go into production. The V-22, commonly called the "Osprey", is controversial because it is new, it is different, and it is a true innovation. By its nature the V-22 is amazing in what it attempts to do and what it accomplishes.

First, lets look at what it is. The V-22 is a twin-engine tilt rotor helicopter / airplane combination aircraft. The two engines are interconnected,
so if one fails, the other can power both rotor systems and the pilot can fly the aircraft to a landing site. The counter rotating airfoils at the end of each wing (Called prop-rotors) are used as propellers in forward flight, and as articulated rotors in vertical take-off and landing modes. It uses
the concepts of differential collective pitch used in tandem rotor helicopters, rotor tilt concepts used in single rotor helicopters, the concept of
movable control surface on the wings like airplanes do, and engine nacelle rotation for transition between flight modes. This aircraft has a lot to
do. Here is the real kicker: The whole thing folds up automatically to take less space on military ships. (See the photo

What makes the V-22 so amazing?

This aircraft has safety built into every aspect of its design. Some examples of this are the triple redundant hydraulic systems with an added
nitrogen bottle emergency blow down for the landing gear should everything else fail. The composite fuselage structure has a metallic wire mesh
built into it to dissipate lightning strikes. The prop-rotors have lights in the rotor tips for night safety and de-icing blankets built into them. They
are designed to fail in such a way that they will turn into strands of composite material upon impact (Broom Stranding). This eliminates the hazard
of large chunks of flying rotor traveling in every direction in a crash situation. The engine and transmission systems have double, triple and
quadruple redundancy built into them. The aircraft can fly with any degree of nacelle tilt in both single and multi engine modes. This would
pose a lubrication problem for the engines if a dual lubrication system were not installed for the level and tilted engine modes of flight. Should the lubrication system run completely dry, the aircraft could fly for an additional 30 minutes without oil. The nose of the aircraft was designed as an anti-plowing structure and the panels on both sides of the cockpit are ballistically jettisonable for rapid egress of the cockpit crew. In a high impact landing, the wings are designed to fail outboard near the engines so wing structures will not contact the fuselage. The self-sealing fuel system has self-closing safety fittings and breakaway fuel lines designed to contain the fuel in a high impact situation and reduce the hazard of post crash fire. Dual automatic flight control systems monitor and adjust control inputs to reduce the workload on the pilots. And this is just the tip of the iceberg. There are so many safety systems built in to this aircraft, one person could not begin to tell you all about them.

Click for a larger picture.

So then, why all of the controversy?

Even though all of the safety information about the aircraft is readily available, some critics of the aircraft still say it is unsafe by design. I have
read numerous articles concerning the safety of the aircraft, which make claims about the susceptibility of the rotor systems to encounter a
phenomenon called Vortex Ring State . For those of you familiar with Settling with Power (Also known as Power Settling in the Naval Aviation
community) as described on this site, Vortex Ring State is the re-circulation of air within the rotor system that makes Settling with Power the
dangerous situation it is. Basically, the rotor system is processing the same air continuously and is not producing enough lift to maintain hovering flight.

Is Vortex Ring State or Settling with Power unique to the V-22?

No, it is not unique at all. Every helicopter can get into it if the situation is allowed to exist. There are three conditions that must exist for Settling with
Power to begin; Significant power applied (Always present at a hover), a descent rate greater than 300 feet per minute, and a near zero airspeed. If
descent rates are not allowed to become excessive, then the aircraft will usually not settle into its own downwash.

Why is Vortex Ring State such an issue with the V-22?

To explain this, let s make a comparison to the most similar aircraft available, the CH-47D Chinook. The V-22 has a maximum gross weight of around
50,000 lbs (52,870 according to the Boeing web site) for vertical takeoff. The CH-47 also has a 50,000 maximum gross weight for vertical takeoff. The
V-22 uses two engines that produce around 4500 Shaft Horsepower (Almost 5000 for USN and USAF models and almost 6000 SHP for single engine
flight). The CH-47D also has two engines that produce 4500 SHP. The engines on the V-22 are interconnected so that both engines, or one engine
can power both rotors. The Chinook also has the engines interconnected so it too can power both rotors with both engines or just one engine.

The main differences between the two aircraft are that the V-22 can fly in airplane mode, and that the comparative size of the rotor systems is dramatically
different. The V-22 uses two 38-foot diameter prop-rotors and the Chinook uses two 60-foot diameter conventional rotors. Basically the V-22 is lifting a
similar maximum weight with 1/3 less rotor diameter. Some of the difference is made up in the design of the prop-rotor and the overall surface area of
the prop-rotors, but there is a significant difference in blade size. Because the V-22 has to do the same job with a smaller diameter rotor system it is
possible that it could be more susceptible to the conditions that create Settling with Power .

Another factor, which could possibly contribute to the creation of Vortex Ring State, is the location of the rotors. On a Chinook, the rotors overlap
one another in path, and the aft rotor sits higher than the forward rotor. On the V-22, the rotors sit at the same height, and are side by side at the
ends of the wings. In certain crosswind conditions during a rapid descent, the rotor-wash from one system could effectively be blown into the other
rotor system causing a possible unstable condition.

One VERY IMPORTANT thing to point out here is that the V-22, once it has encountered Settling With Power (Army) or Power Settling (Navy), has a unique ability to get out of it. It does so without aggravation of the situation that normal helicopters do not have. The nacelles have a control switch which can be "Beeped" (Quick pressing of the switch to make small movements) up or down to change the angle of the nacelle. This can increase forward airspeed quickly without changing the pitch of the prop-rotors. Increasing airspeed and flying into clean air is the way to get out of the Vortex Ring State which is responsible for the "Settling" issues. The V-22 has the unique ability to increase airspeed without changing rotor pitch and can accomplish the airspeed increase much faster than any normal rotary wing aircraft.

Wasn't there a crash involving Vortex Ring State and a V-22?

Yes. This is where a lot of the media press has been coming from about the V-22 and Vortex Ring State. The crash was ruled to be pilot error.
Now, I know what you are thinking: The military ALWAYS blames the pilots.

In this case, it was pilot error according to the report used in the Senate Hearings on the viability of the V-22. The V-22 that crashed was in a
two-ship formation when the lead ship started a rapid deceleration. The trailing ship (The one that crashed) followed the lead ship beyond the
point where it was safe and entered a descent that was in excess of 3000 feet per minute (3900+ FPM according to the attached file). When the pilot tried to recover from the excessive descent, the aircraft impacted the ground and all aboard were killed. The families of the crewmembers have filed a lawsuit saying that the aircraft itself was to blame. However, there is no reasonable person who would assume that a pilot induced descent in excess of 10 times the minimum
required rate of descent to enter Vortex Ring State would be the fault of the aircraft. While I offer my condolences to the families of those who
were killed, I must state that the excessive rate of descent was the problem here, not the aircraft design. Had the pilot broken formation and
departed the landing zone to set up for a new approach, he probably would be alive today. Does that mean I am saying that the aircraft is
perfect? No. It does have some problems that need to be worked out, but this specific situation is not a case where the aircraft design is at fault.

Read the actual report from the panel to review the V-22.
If the file does not open, right click on the file and save it to your hard drive. Open the file in MS Word.Page 1Page 2Page 3Entire report in Adobe .PDF format.
Editors Note: The one part of this report that I disagree with was that the pilots were said to not be clearly understanding of the safety threat caused by Vortex Ring State / Power Settling (Navy Terminology)/ Settling with Power (Army Terminology). All military helicopter pilots should be well versed in the dangers associated with this issue, as it is a major part of their initial flight training.

Does the ability to get into Vortex Ring State make the V-22 unsafe?

No. Almost every helicopter ever made has some unique characteristics. If the pilots are not aware of these characteristics, if they are not
properly trained to recognize situations and do not adjust their procedures accordingly, then they could end up in a very serious situation.
For example; The UH-1 Iroquois (Huey) had major issues when it first went into production. The UH-1 had then (And still has) a rotor
system that pivots at the mast. If the pilot unloads the rotor system by performing a negative G maneuver, excessive violent blade
flapping can occur. When this happens, the hub of the rotor system will contact the mast and it will make a thump noise (Referred
to as Mast Bumping in the operators manual). It will bump once or twice and then the rotor system will separate from the aircraft.
A lot of pilots were killed before they figured out what the problem was. The official fix (According to the operators manual): Do not
perform negative G maneuvers. The aircraft flew for almost 30 years before they created a modification to the mast which included
rubber covered springs to help reduce the severity of a mast bump, but they still do not eliminate the problem completely. Is the
Huey unsafe because of this situation? No. It is one of the safest helicopters ever produced. It is just a situation that any Huey
pilot knows to avoid. The same goes for the V-22. If I were a V-22 pilot, I would avoid rapid descents and hovering in excessive
crosswinds. I would also avoid the downwash of other aircraft. This may require the need for loose formations on landing, which
is always a much safer situation for any multi-helicopter operation.

Here is a comparison chart to other aircraft in development. By looking at the chart, it is easy to see that this aircraft, which is so revolutionary in design, stacks up comparibly to conventional aircraft developmental year accident rates.

What are the other issues concerning the V-22?

One other issue is the claim that the V-22 is not able to autorotate from a high hover. I have read articles on the Boeing and Bell web
sites where people have claimed that the rotors will not freewheel should both engines fail. On the Bell web site there is a series of V-22
newsletters entitled Osprey Facts . The January 2001 issue has an article written by Col. Nolan Schmidt who states very clearly that
the freewheeling units that had been claimed to be removed early on in the development of the V-22 were in actuality, still installed in
every Osprey that has ever flown. The nice thing about the V-22 is that it has two engines, which are interconnected. If one should fail,
the aircraft can fly safely on one engine. If both engines should fail (Which is very rare), then it can glide down should it have sufficient
forward airspeed. Also, if you have sufficient airspeed and one engine working, you can make a running landing with the nacelles at a
60-degree pitch (As recommended by the manufacturer). If you are at a low airspeed, high altitude hover, or a number of other situations
and you lose both engines, then it is just not your day. That is not just in a V-22, that is in any rotary wing aircraft.

Here is a photo of a V-22 at 60 degrees of nacelle tilt.

Autorotation from a high hover is a limitation on most, if not all helicopters. The UH-1 has a performance chart, which shows that any
autorotation attempted below certain airspeeds and at certain heights above the ground will most likely not be successful. Some
people call this chart the Dead Man s Chart . It is another situation where the pilot knows the risks but sometimes he/she just has
to take them to complete the mission. People in the logging business who use helicopters, fly at very high hovers with little or no
forward airspeed. They recognize that they are flying in a dangerous flight parameter most of the time and accept the risk as part of the job.

What other aircraft have had growing pains?

The OH-58 (Before the D model) series of aircraft have always suffered from weak engines that are prone to heat damage. The temperature
limitations offer a narrow power band and do not lend themselves to rapid power changes. They also had a problem with lack of tail rotor
authority problems. The D model never has been able to autorotate well. It has been made worse since they have now hung more weight
on it. The pilot of a D has to be very diligent when autorotation occurs that they do not let the rotor RPM decay. With the 4 bladed low
inertia rotor system, the rotor RPM is hard to recover should it fall below normal limits.

The UH-60 Blackhawk had plenty of problems with the stabilator when they first were produced. The stabilator would encounter electrical
interference and change position all by itself. It would change the center of gravity of the aircraft and they were falling out of the sky on a
regular basis. Once they figured out what the problems were, they made the appropriate changes and now the UH-60 is one of the best
aircraft the Army has. When I was in flight school, no one I knew wanted to fly a Lawn Dart , or a Black Rock . Time and modification of
the airframe have changed this attitude toward the UH-60.

The AH-64 had several problems when they first came out too. We heard stories and saw photos of dual engine failures. The movie Firebirds used one of the original crashed AH-64 Apaches in the filming. As with any other aircraft, they worked out the problems and the Apache is now a great fighting machine.
The CH-47 had a problem with control tubes made from aluminum. When there was a fire in the engine gearbox and hydraulic fluid would leak out, it would catch on fire and surround the control tubes. The aluminum tubes would melt and the pilot would lose control of the aircraft since the rotor systems were no longer connected to the control linkages. They made some changes in the hydraulic fluid and the control tubes so this would no longer be an issue. Like many other aircraft, the aircraft mentioned in these examples had their initial problems. Over time, the problems were discovered and corrective measures were applied.

Aviation is a learning experience. Unfortunately, some people will lose their life in the learning process. Every pilot knows that they are at risk every time they take to the air, and manufacturers of aircraft are spending more time and money to design safer aircraft than at any point in the history of aviation. This aircraft design deserves to be pursued and the problems given time to be worked out. The V-22 is a major innovation for VTOL aircraft and every effort should be made to see it to maturity and into full scale production.

Fort Worth, TX - January 26, 2006 - Bell Helicopter, a unit of Textron Inc, has announced
that its TR918 Eagle Eye Unmanned Aircraft System
(UAS) lifted off the ground for the first time today when it achieved the
first flight milestone in this ground breaking, vertical-lift unmanned
aircraft program. At 8:54 a.m. (CST) the vehicle lifted vertically off the
ground hovered for nine minutes, executed yaw and translation maneuvers and
then landed safely on the ground. The vehicle flew a second flight within 30
minutes of the maiden flight's landing.

The Civil Tiltrotor Flys

I was fortunate enough to go and see this aircraft in Arlington last month and attend the Heli-Expo held at the Dallas Convention Center.

Arlington, Texas, March 7, 2003: Aviation history was made today with the maiden flight of the world s first civil tiltrotor, the Bell/Agusta Aerospace BA609. The nine-passenger aircraft, jointly developed by Bell Helicopter Textron and Agusta, hovered at an altitude of 50 feet, performed left and right peddle turns, both forward and aft flight maneuvers, four take-offs and landings, nacelle position changes and stability testing for .6 flight hours (36 minutes) before setting down. The first flight follows several weeks of ground runs and taxi testing for the BA609 conducted at Bell s Arlington Flight Research Center.
Today s first flight of the BA609 is truly an historic occasion for it marks the first flight of an aircraft that will be available to the public that can not only fly with the high speed and range of an airplane but can take-off, hover and land with the versatility of a helicopter, stated Bell Helicopter s Chairman and CEO John Murphey, adding, Until today, commercial helicopters were limited to a top speed of about 150 knots. The BA609 smashes through that barrier with a top speed approaching 300 knots. This achievement is as remarkable as when the Bell X-1 first broke the sound barrier over 50 years ago.

Update: 11/13/02 Sent to me personally from Bob Leder at Navair:

Subject: Osprey Reaches 100-flight hour Mark

Date: 08-Nov-02

News Release Number: EHD200211081

News Release Copy: By Ward Carroll, NAVAIR Public Affairs, V-22

The V-22 Integrated Test Team recently surpassed 100 hours flown since the program's return to flight in late May of this year. The milestone was reached by Osprey No. 10 on a three-hour test flight crewed by Maj. Shawn Healy, Maj. Paul Ryan, and Staff Sgt. Michael Snyder.

"It's a great feeling," said Healy. "All test points were met on our flight, which is representative of how things have gone lately. We've done a lot to get the program where it is."

"The integrated test team has gelled," Fred Madenwald, Integrated Test Team (ITT) Contract Flight Test Director, said. Madenwald credits the ITT concept with moving the Osprey program effectively forward. "The Marines, Air Force, Dyncorp, and Rolls-Royce have all come together to make things happen," he said. "Like all test programs we've had some unplanned problems, but the way we're configured allows us to solve them quickly."

While justifiably proud of reaching the 100-hour milestone, the V-22 program isn't about to slacken its intensity. In the coming months the ITT will be executing the High Rate of Decent (HROD) test plan as well as accepting their fifth aircraft from the Bell-Boeing plant in Amarillo, Texas.

"Passing the 100-hour mark is a big step toward proving the V-22 is a safe aircraft," Madenwald said, "but it's just one step. We're not going to let up until the Osprey is supporting the fleet, and even then we'll still be
around to help it realize its full potential. The V-22 is an amazing airplane."

NAVAIR provides advanced warfare technology through the efforts of a seamless, integrated, worldwide network of aviation technology experts. From professional training to carrier launch and recovery; from sensor data to precision targeting and real-time communications; from aircraft and
weapons development to successful deployment and sustainment; NAVAIR provides dominant combat effects and matchless capabilities to the American warfighter.

Click Here for a link to the U.S. Airforce that explains what is currently happening (As of 9/13/02) with the Airforce V-22 project testing. Special thanks go out to Jeff Bailey of Navarre, FL. for sending this link.

2/25/03
This was sent to me back in 2001 by Harry Dunn, a self appointed leader of an unofficial group who calls themselves the "Red Ribbon Panel". Harry has flat out accused me of many differnt things, he has been very rude to me in his correspondence and I do not take much of what he says seriously. I did however, want to post both sides of the story to be fair to those who are supportive and critical of the V-22 project.

I must add that Harry was reluctant to answer any questions for me, and I am still trying to find out exactly what his points and intentions are. Harry has not given me any more information to this day to support his claims. He has been less than forthcoming with me from day 1, cocealing the fact that his group was "unofficial". I still await his answers on the questions of what Bell / Boeing are, (in his words) "Hiding". If he ever lets me know, I will try to post that as well. I do not think that he will tell me anything more than I already know about him, his organization or his motives. I did find out that he has an interest in a rival defense contractor, which might partially explain why he feels so strongly about cancelling this project.

I do agree with the idea that more testing should be conducted for the V-22, and so does everyone else involved.

*****************************
Tests 'last chance' for V-22

By BOB COX
Star-Telegram Staff Writer

A Pentagon official orders rigorous flight testing of the Osprey to prove "once and for all" whether it is safe.

The Pentagon's chief weapons buyer said Friday that he continues to doubt the safety of Bell Helicopter Textron's V-22 Osprey, and ordered a new round of flight tests for the tilt-rotor aircraft.

Pete Aldridge, undersecretary of defense for acquisition, said new testing will begin in April and take at least two years.

He said it would determine "once and for all" if the V-22 - which was involved in two fatal crashes last year that killed 23 Marines - can be a safe and effective aircraft.

"I've had some serious doubts about the safety, reliability and operational suitability of the V-22," Aldridge said during a Pentagon briefing. "I personally still have some doubts. But the only way to find out once and for all is to put it back into flight testing."

After nearly two decades of work on the V-22 and more than $13 billion in expenses, some analysts say that the new testing amounts to one last chance for the troubled aircraft, which Bell builds in partnership with Boeing.

"This is the last chance to prove that the V-22 is safe," said Loren Thompson of the Lexington Institute, a longtime advocate of the Osprey.

The small fleet of about two dozen test and production V-22s has been grounded since the last crash on Dec. 11, 2000, which killed the Marines' two most experienced pilots.

That accident was traced to a ruptured hydraulic line and flight control computer software problems. An April 2000 crash that killed 19 Marines was pegged to an aerodynamic phenomenon that caused the aircraft to stall and spin out of control.

Aldridge's decision was not unexpected. In late April, a panel of military officers and aerospace experts recommended that the V-22 program continue, but with more exhaustive testing. A NASA-led panel recently came to a similar conclusion.

But defense analysts said that Aldridge's reluctant approval of the test program sent a strong signal to the V- 22 lobby. "I think we've known for some time that the senior political leadership in the Pentagon was less enthusiastic about the V-22 than the military," Thompson said.

Bell spokesman Bob Leder said the company is ready to proceed with the prescribed test program. About 2,000 jobs at Bell's Fort Worth-area plants are tied to the V-22.
"We have very similar goals to undersecretary Aldridge," Leder said. "We want the V-22 to be a completely safe aircraft, thoroughly tested and a very effective aircraft."

The Osprey has long been heralded as a revolutionary aircraft that could replace slower helicopters in transporting troops into battle. By rotating its engines from a vertical to a horizontal position, the V-22 can take off and land vertically like a helicopter and then fly with the greater speed of a conventional aircraft.

But throughout years of development and testing, the V-22 has been plagued by technical problems, cost increases and an unenviable safety record. There have been four V-22 crashes, including the two last year.

"The engineering people who built the Osprey grossly underestimated the difficulties of this tilt-rotor, dual-rotor phenomena," Aldridge said.

Critics, including some Defense Department officials, have said that the Navy, Marines and the two contractors rushed through an inadequate testing program and ignored warning signs in an effort to speed the V-22 into full production.

Aldridge warned that he would allow no shortcuts this time. "This new flight testing program will be much more comprehensive than that previously planned," he said. He also said no troops would be aboard during the test flights, which would be conducted by both military and company test pilots.

Aldridge said the flight testing will have to prove that the V-22 can be operated safely in realistic situations, including being able to maneuver when in helicopter mode and hovering near the ground or flying at low forward speed.

He said he is particularly concerned about the aircraft's tendency to roll when pilots encounter a turbulent condition known as vortex ring state, which is believed to have caused the April 2000 crash. He also wants proof that the V-22 can be flown safely in the wakes of other aircraft or when operated from the decks of ships.

Those words cheered some V-22 critics who believe that their concerns have largely been dismissed by Bell, Boeing and the Marines.

"We are elated. ... The flight test program will focus on combat maneuvering, low-speed maneuvering and hover," said Harry Dunn, a retired Air Force helicopter pilot and aeronautical engineer. Dunn is coordinator of an unofficial group of pilots and engineers that calls itself the Red Ribbon Panel.

"All of our analysis shows this aircraft cannot safely operate in those conditions," said Dunn, whose group has been sending information critical of the V-22 to Aldridge since May.

Marine Corps leaders "are encouraged and pleased" with Aldridge's announcement, Capt. David Nevers said. The flight testing program "will proceed very cautiously. Our progress is going to be governed by our success in meeting planned objectives," and not by a timeline, the Marine spokesman said.

Bell has laid off about 350 workers since September, in part because of V-22 delays. Production of the aircraft has slowed to a crawl, and Aldridge said the Pentagon will buy no more than 10-12 a year until the aircraft is proven. Only nine will be ordered in 2002.

Aldridge had been expected to make his decision several weeks ago, leading some analysts to believe that he may have wished to terminate the V-22 program. But he faced deep political support for the aircraft and the perception of cutting a weapons program during the ongoing war in Afghanistan, they said.

"It makes sense to flight test to find out if this aircraft is aerodynamically sound," said defense analyst Michael O'Hanlon of the Brookings Institution. But he said the Marines need to be working on a plan to buy new helicopters in case the V-22 is not found to be suitable.

"We don't know enough yet about this technology to not have a backup plan," he said. Congressional supporters of the V-22 applauded the decision by Aldridge.

The Osprey's most vocal proponent, Rep. Curt Weldon, R-Pa., said, "We cannot ensure the ultimate safety of the aircraft unless we test vigorously and move ahead with the next phase of the program. We need to get the V- 22 back in the air."

Update: 11/2/11

So...with all of the past controversy, how is the V-22 actually doing in the field?

A total of 10 Marine Corps and two Air Force Special Operations Command Osprey squadrons are operational today, and the two services have together logged 16 successful combat, humanitarian,
ship-based or Special Operations deployments since 2007. The worldwide Osprey fleet has amassed more than 120,000 flight hours, with nearly half of those hours logged in the past two years.

Safety, survivability and mission efficiency have become hallmarks of the operational fleet. According to Naval Safety Center records, the MV-22 has had the lowest Class A mishap rate of any tactical
rotorcraft in the Marine Corps during the past decade. Fiscal year 2010 Navy flight-hour cost data also show that the Osprey has the lowest cost per seat-mile (cost to transport one person over a distance
of one mile) of any U.S. naval transport rotorcraft.

The V-22 Osprey is a joint service, multirole combat aircraft that uses tiltrotor technology to combine the vertical performance of a helicopter with the speed and range of a fixed-wing aircraft. With its
nacelles and rotors in vertical position, it can take off, land and hover like a helicopter. Once airborne, its nacelles can be rotated to transition the aircraft to a turboprop airplane capable of high-speed,
high-altitude flight.

More than 150 Osprey tiltrotors are currently in operation. Marine Corps MV-22s are currently deployed in Afghanistan supporting Operation Enduring Freedom and with the 22nd Marine Expeditionary
Unit supporting contingency operations, while AFSOC CV-22s are deployed in support of ongoing Special Operations missions. (BHTI)

Special thanks go out to Bell Helicopter Textron and Boeing who made the photos and graphics available on their websites, and who sent me as much information on the V-22 as I could handle at my request. Thanks to Bob Leder, Manager of Communications Operations, at Bell and NAVAIR's L.B. "Gidge" Dady for answering specific performance and emergency procedure questions. A special thanks to "Dan" at the "Jim Lehrer News Hour" who gave me the motivation to study up on this amazing aircraft.

Airplane Pilot: Can you land on the numbers? Helicopter Pilot: Every time!